[PATCH net 0/4] a few corrections for SOCK_SUPPORT_ZC

[PATCH net 0/4] a few corrections for SOCK_SUPPORT_ZC

[Pavel Begunkov]

There are several places/cases that got overlooked in regards to
SOCK_SUPPORT_ZC. We're lacking the flag for IPv6 UDP sockets and
accepted TCP sockets. We also should clear the flag when someone
tries to hijack a socket by replacing the ->sk_prot callbacks.

Pavel Begunkov (3):
  udp: advertise ipv6 udp support for msghdr::ubuf_info
  net: remove SOCK_SUPPORT_ZC from sockmap
  net/ulp: remove SOCK_SUPPORT_ZC from tls sockets

Stefan Metzmacher (1):
  net: also flag accepted sockets supporting msghdr originated zerocopy

 include/net/sock.h  | 7 +++++++
 net/ipv4/af_inet.c  | 2 ++
 net/ipv4/tcp_bpf.c  | 4 ++--
 net/ipv4/tcp_ulp.c  | 3 +++
 net/ipv4/udp_bpf.c  | 4 ++--
 net/ipv6/udp.c      | 1 +
 net/unix/unix_bpf.c | 8 ++++----
 7 files changed, 21 insertions(+), 8 deletions(-)

-- 
2.38.0

[PATCH net 1/4] udp: advertise ipv6 udp support for msghdr::ubuf_info

[Pavel Begunkov]

Mark udp ipv6 as supporting msghdr::ubuf_info. In the original commit
SOCK_SUPPORT_ZC was supposed to be set by a udp_init_sock() call from
udp6_init_sock(), but
d38afeec26ed4 ("tcp/udp: Call inet6_destroy_sock() in IPv6 ...")
removed it and so ipv6 udp misses the flag.

Cc: <stable@vger.kernel.org> # 6.0
Fixes: e993ffe3da4bc ("net: flag sockets supporting msghdr originated zerocopy")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 net/ipv6/udp.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 129ec5a9b0eb..bc65e5b7195b 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -66,6 +66,7 @@ int udpv6_init_sock(struct sock *sk)
 {
 	skb_queue_head_init(&udp_sk(sk)->reader_queue);
 	sk->sk_destruct = udpv6_destruct_sock;
+	set_bit(SOCK_SUPPORT_ZC, &sk->sk_socket->flags);
 	return 0;
 }
 
-- 
2.38.0

[PATCH net 2/4] net: remove SOCK_SUPPORT_ZC from sockmap

[Pavel Begunkov]

sockmap replaces ->sk_prot with its own callbacks, we should remove
SOCK_SUPPORT_ZC as the new proto doesn't support msghdr::ubuf_info.

Cc: <stable@vger.kernel.org> # 6.0
Reported-by: Jakub Kicinski <kuba@kernel.org>
Fixes: e993ffe3da4bc ("net: flag sockets supporting msghdr originated zerocopy")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 include/net/sock.h  | 7 +++++++
 net/ipv4/tcp_bpf.c  | 4 ++--
 net/ipv4/udp_bpf.c  | 4 ++--
 net/unix/unix_bpf.c | 8 ++++----
 4 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index 22f8bab583dd..5db02546941c 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1889,6 +1889,13 @@ void sock_kfree_s(struct sock *sk, void *mem, int size);
 void sock_kzfree_s(struct sock *sk, void *mem, int size);
 void sk_send_sigurg(struct sock *sk);
 
+static inline void sock_replace_proto(struct sock *sk, struct proto *proto)
+{
+	if (sk->sk_socket)
+		clear_bit(SOCK_SUPPORT_ZC, &sk->sk_socket->flags);
+	WRITE_ONCE(sk->sk_prot, proto);
+}
+
 struct sockcm_cookie {
 	u64 transmit_time;
 	u32 mark;
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
index a1626afe87a1..c501c329b1db 100644
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -607,7 +607,7 @@ int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)
 		} else {
 			sk->sk_write_space = psock->saved_write_space;
 			/* Pairs with lockless read in sk_clone_lock() */
-			WRITE_ONCE(sk->sk_prot, psock->sk_proto);
+			sock_replace_proto(sk, psock->sk_proto);
 		}
 		return 0;
 	}
@@ -620,7 +620,7 @@ int tcp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)
 	}
 
 	/* Pairs with lockless read in sk_clone_lock() */
-	WRITE_ONCE(sk->sk_prot, &tcp_bpf_prots[family][config]);
+	sock_replace_proto(sk, &tcp_bpf_prots[family][config]);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(tcp_bpf_update_proto);
diff --git a/net/ipv4/udp_bpf.c b/net/ipv4/udp_bpf.c
index ff15918b7bdc..e5dc91d0e079 100644
--- a/net/ipv4/udp_bpf.c
+++ b/net/ipv4/udp_bpf.c
@@ -141,14 +141,14 @@ int udp_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)
 
 	if (restore) {
 		sk->sk_write_space = psock->saved_write_space;
-		WRITE_ONCE(sk->sk_prot, psock->sk_proto);
+		sock_replace_proto(sk, psock->sk_proto);
 		return 0;
 	}
 
 	if (sk->sk_family == AF_INET6)
 		udp_bpf_check_v6_needs_rebuild(psock->sk_proto);
 
-	WRITE_ONCE(sk->sk_prot, &udp_bpf_prots[family]);
+	sock_replace_proto(sk, &udp_bpf_prots[family]);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(udp_bpf_update_proto);
diff --git a/net/unix/unix_bpf.c b/net/unix/unix_bpf.c
index 7cf14c6b1725..e9bf15513961 100644
--- a/net/unix/unix_bpf.c
+++ b/net/unix/unix_bpf.c
@@ -145,12 +145,12 @@ int unix_dgram_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool re
 
 	if (restore) {
 		sk->sk_write_space = psock->saved_write_space;
-		WRITE_ONCE(sk->sk_prot, psock->sk_proto);
+		sock_replace_proto(sk, psock->sk_proto);
 		return 0;
 	}
 
 	unix_dgram_bpf_check_needs_rebuild(psock->sk_proto);
-	WRITE_ONCE(sk->sk_prot, &unix_dgram_bpf_prot);
+	sock_replace_proto(sk, &unix_dgram_bpf_prot);
 	return 0;
 }
 
@@ -158,12 +158,12 @@ int unix_stream_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool r
 {
 	if (restore) {
 		sk->sk_write_space = psock->saved_write_space;
-		WRITE_ONCE(sk->sk_prot, psock->sk_proto);
+		sock_replace_proto(sk, psock->sk_proto);
 		return 0;
 	}
 
 	unix_stream_bpf_check_needs_rebuild(psock->sk_proto);
-	WRITE_ONCE(sk->sk_prot, &unix_stream_bpf_prot);
+	sock_replace_proto(sk, &unix_stream_bpf_prot);
 	return 0;
 }
 
-- 
2.38.0

[PATCH net 3/4] net/ulp: remove SOCK_SUPPORT_ZC from tls sockets

[Pavel Begunkov]

Remove SOCK_SUPPORT_ZC when we're setting ulp as it might not support
msghdr::ubuf_info, e.g. like TLS replacing ->sk_prot with a new set of
handlers.

Cc: <stable@vger.kernel.org> # 6.0
Reported-by: Jakub Kicinski <kuba@kernel.org>
Fixes: e993ffe3da4bc ("net: flag sockets supporting msghdr originated zerocopy")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 net/ipv4/tcp_ulp.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/ipv4/tcp_ulp.c b/net/ipv4/tcp_ulp.c
index 7c27aa629af1..9ae50b1bd844 100644
--- a/net/ipv4/tcp_ulp.c
+++ b/net/ipv4/tcp_ulp.c
@@ -136,6 +136,9 @@ static int __tcp_set_ulp(struct sock *sk, const struct tcp_ulp_ops *ulp_ops)
 	if (icsk->icsk_ulp_ops)
 		goto out_err;
 
+	if (sk->sk_socket)
+		clear_bit(SOCK_SUPPORT_ZC, &sk->sk_socket->flags);
+
 	err = ulp_ops->init(sk);
 	if (err)
 		goto out_err;
-- 
2.38.0

[PATCH net 4/4] net: also flag accepted sockets supporting msghdr originated zerocopy

[Pavel Begunkov]

From: Stefan Metzmacher <metze@samba.org>

Without this only the client initiated tcp sockets have SOCK_SUPPORT_ZC.
The listening socket on the server also has it, but the accepted
connections didn't, which meant IORING_OP_SEND[MSG]_ZC will always
fails with -EOPNOTSUPP.

Fixes: e993ffe3da4b ("net: flag sockets supporting msghdr originated zerocopy")
Cc: <stable@vger.kernel.org> # 6.0
CC: Pavel Begunkov <asml.silence@gmail.com>
Cc: Jakub Kicinski <kuba@kernel.org>
CC: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/io-uring/20221024141503.22b4e251@kernel.org/T/#m38aa19b0b825758fb97860a38ad13122051f9dda
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 net/ipv4/af_inet.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 3dd02396517d..4728087c42a5 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -754,6 +754,8 @@ int inet_accept(struct socket *sock, struct socket *newsock, int flags,
 		  (TCPF_ESTABLISHED | TCPF_SYN_RECV |
 		  TCPF_CLOSE_WAIT | TCPF_CLOSE)));
 
+	if (test_bit(SOCK_SUPPORT_ZC, &sock->flags))
+		set_bit(SOCK_SUPPORT_ZC, &newsock->flags);
 	sock_graft(sk2, newsock);
 
 	newsock->state = SS_CONNECTED;
-- 
2.38.0

Re: [PATCH net 0/4] a few corrections for SOCK_SUPPORT_ZC

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Thu, 27 Oct 2022 00:25:55 +0100 you wrote:
> There are several places/cases that got overlooked in regards to
> SOCK_SUPPORT_ZC. We're lacking the flag for IPv6 UDP sockets and
> accepted TCP sockets. We also should clear the flag when someone
> tries to hijack a socket by replacing the ->sk_prot callbacks.
> 
> Pavel Begunkov (3):
>   udp: advertise ipv6 udp support for msghdr::ubuf_info
>   net: remove SOCK_SUPPORT_ZC from sockmap
>   net/ulp: remove SOCK_SUPPORT_ZC from tls sockets
> 
> [...]

Here is the summary with links:
  - [net,1/4] udp: advertise ipv6 udp support for msghdr::ubuf_info
    https://git.kernel.org/netdev/net/c/8f279fb00bb2
  - [net,2/4] net: remove SOCK_SUPPORT_ZC from sockmap
    https://git.kernel.org/netdev/net/c/fee9ac06647e
  - [net,3/4] net/ulp: remove SOCK_SUPPORT_ZC from tls sockets
    https://git.kernel.org/netdev/net/c/e276d62dcfde
  - [net,4/4] net: also flag accepted sockets supporting msghdr originated zerocopy
    https://git.kernel.org/netdev/net/c/71b7786ea478

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html